Prognostic factors and survival in low grade gliomas of the spinal cord: A population-based analysis from 2006 to 2012.

PURPOSE

Primary spinal cord tumors are rare, and evidence-based management of these patients remains a source of controversy. This study used a large cohort of low-grade spinal cord astrocytomas to determine the effectiveness of prognostic factors and survival.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) cancer registry was used to identify patients with WHO grade I-II primary spinal cord astrocytomas from 1973 to 2012; however, patients before 2006 were excluded due to ambiguity diagnosis. Univariate and multivariate Cox proportional hazard models were created to compare survival across covariates and summarized using the Kaplan-Meier method.

RESULTS

A total of 561 patients with low-grade glioma (astrocytoma) were identified. Among these, 15.5% of patients received a gross total resection (GTR), 26.1% subtotal resection (STR), and 46.2% unidentified extent of resection. 59.4% did not receive any radiation therapy at any point of the treatment course, while 40.6% underwent radiation therapy. In our cohort, only patients with GTR demonstrated statistically improved survival (HR: 0.22, P < 0.001). Patients with STR had nearly identical survival compared to patients with no surgery (HR: 0.98), and radiotherapy was associated with increased odds of mortality (HR: 1.47, P < 0.001). Multivariate analysis demonstrated a significant survival benefit among patients with younger age, GTR and absence of radiotherapy. Histologic grade did not statistically impact survival.

CONCLUSION

Our study suggests that GTR results in improved survival among patients with low-grade gliomas within the spinal cord. Future, considerable data research efforts will aim to better define the role of radiotherapy and tumor grading in this patient population.